Tools
Colour blindness simulator
See how people with different types of colour blindness perceive your colours and images.
Original
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Normal vision
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Colour blindness affects roughly 8% of men and 0.5% of women worldwide. The most common types are red–green deficiencies (protanopia and deuteranopia, and their milder forms).
When designing, make sure there is enough contrast and don’t rely on colour alone to convey information. Use patterns, labels or icons as additional cues.
About this tool
Simulate how people with colour vision deficiencies see colour: protanopia, deuteranopia and tritanopia, their milder forms (protanomaly, deuteranomaly and tritanomaly), achromatopsia and achromatomaly. It helps you catch charts whose series blur together, red and green warnings that look alike, or brand palettes that lose their meaning for part of your audience.
In “Colour mode”, pick a colour with the swatch or type its hex code: you will see all nine vision types at once, each with its value and severity, plus a side-by-side comparison with the original. In “Image mode”, drop, choose or paste an image, select a vision type and compare original and simulation next to each other; tap either to enlarge it.
Images are processed in your browser on a canvas and never leave your device. The simulation uses approximate linear matrices, good for design work but not for diagnosis: everyone perceives colour a little differently. Very large images may take a few seconds. There is currently no option to download the simulated image.
Frequently asked questions
What is the most common type of colour blindness?
Deuteranomaly, a reduced sensitivity to green, which affects around 5% of men. Red–green deficiencies as a group are by far the most common.
What is the difference between protanopia and protanomaly?
In protanopia the red-sensitive cones are missing; in protanomaly they are present but work less well. The first is a complete form, the second a partial one.
Which colour combinations should I avoid?
Red with green, green with brown and blue with purple cause the most trouble. If you use them, add labels, icons or patterns so meaning doesn’t rely on colour alone.
Can I use this as a colour blindness test?
No. It shows an approximation of how colours appear but does not diagnose anything. To find out whether you are colour blind, see an optometrist or eye doctor.